Several different arrangements are already known for joining sheets or panels edge-to-edge in a display system or arrangement by utilising a magnetic attractive force.
Several ways of combining pictures and text having dimensions considerably larger than the dimensions of a single utilised sheet or panel, for the purpose of providing information are already known and, with reference to the present invention, it should be mentioned that it is already known to join a plurality of such panels edge-to-edge with the aid of magnetised strip arrangements initiating the requisite magnetic attractive forces towards each other.
More specifically it is in this respect known for a first edge portion of a first panel to be detachably joined to a second edge portion of a second panel, a first permanently magnetised strip being applied to said first edge portion and a second permanently magnetised strip being applied to said second edge portion, and the magnetised strips being assigned such magnetisation directions in relation to each other that, in a position where the edge portions are in proximity and/or co-operating with each other, they assume a position firmly attracted to each other, said strips consisting of a composite material different from the material of the panels or the sheets and with the strips attached by means of adhesive to said edge portions of the panel.
In this connection it is known to use a PVC material for the material of the panel, which has a modulus of elasticity of approximately 2600 MPa (megapascal or N/m2) and to use an elastic plastic material for the magnetised strip or magnetic strip (1.7×6 mm), which has a modulus of elasticity of approximately 30-35 MPa.
In this respect the magnetic strips pertaining to the panel are suited for mechanical and magnetic co-operation with rails or support points located behind them which are also assigned permanent magnetisation or a magnetically attracting metal
In connection with this arrangement it is thus already known to utilise permanently magnetised strips having a thickness dimension lying usually within the range of about 1.5 to 2.0 mm and having a width dimension between approximately 6 and 12 mm.
These permanently magnetised strips may be polarised in sections 1.5 mm wide or may be N-S polarised in the transverse direction.
It is already known that when a panel is to be rolled up, if one or both lengthways edge portions have been provided with magnetised strips of such thickness, the inner rolling radius for the panel must be rather large so that tensile and compressive forces, as well as axial stress related forces in the edge portions of the panel and the magnetised strip and the attachment means used, will not cause such high stresses that plastic deformation occurs or that the attachment means used slips or is released from its attachment to the panel.
It is also obvious that the spiral shape produced when the panel is rolled up acquires a pitch which is at least dependent on the thickness of the strip and of the panel. Thin panels in particular are extremely difficult to handle when fully rolled up since they become heavy at the end or edge due to the weight of the magnetic strips.
It is also known per se that a maximised magnetic attractive force between the edge portions of the panels must be sufficiently strong to cause these edge portions to abut each other tightly even in the event of slight forces being exerted on the exposed surfaces of the panels.
The magnetic attractive force necessary for this is well tested and thus known.
Taking into consideration the specifics associated with the present invention it may also be mentioned that it is known per se to apply relatively thick magnetic strips (e.g. 1.5-2.0 mm) to the laterally oriented edge portions of one or more sheets or panels so that adjacent sheets can be aligned edge-to-edge without, or substantially without any obvious join between the sheets and where the magnetic attractive force is developed between N/S and S/N magnetised magnetic strips in the transverse direction. Magnetic strips having a thickness of 1.5 to 2.0 mm and a width of 6-12 mm can thus act towards each other edge-to-edge or end surface to end surface.
Display arrangements of this design, to which the present invention is particularly directed, are sold under the description of goods or trademark “Chronoexpo 2”, the deign of which is disclosed on “Internet” (Http://www.chronoexpo.com/site/index.html)
Account of the Present Invention
Technical Problems
Taking into consideration the fact that the technical deliberations one skilled in the art must perform in order to offer a solution to one or more of the technical problems posed are initially an insight into the measures and/or the sequence of measures to be taken and a choice of the means required, and on the basis thereof, the following technical problems are no doubt relevant when producing the present invention.
Taking into consideration the state of the art, as described above, it should be deemed a technical problem in an arrangement enabling edge-to-edge joining, by means of a magnetic attractive force, of a first edge portion of a first panel in a display system to a second edge portion of a second panel, to be able to create such prerequisites that a panel with magnetised strips applied to one edge portion or both edge portions can be rolled in a tight spiral to cylindrical shape (substantially cylindrical shape) having a considerably smaller least diameter than that offered in previously known panels having magnetised strips applied on one edge portion or both edge portions and which shall be rolled up or unrolled from this cylindrical shape to produce a flat orientation.
A technical problem also exists in being able to create such prerequisites that the pitch for spirally rolling the panel with magnetised strips applied, to cylindrical shape, can be chosen considerably less than has been previously possible.
It is furthermore a technical problem to be able to create such prerequisites that a panel with edge-related magnetised strips or thin magnetic strips can be rolled onto a roller-blind rod or rolled up for transportation without a rod but with a relatively small least diameter, e.g. about 10-30 mm.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with, utilising thin magnetic strips, still being able to create prerequisites for sufficiently high magnetic attractive force between the edge portions of the panels and/or the edge surfaces of adjacent magnetic strips, which high attractive force can join with or somewhat exceed the attractive force that the end portions of thick magnetic strips are known to be able to offer.
A technical problem is also entailed in being able to create such prerequisites that, when said magnetised strips consist of a material different from the material of the panel, conditions shall be created in a attachment means or a layer for relatively low axial stress, in spite of a small radius of curvature having been selected for the panel on which the magnetised strip or strips is/are applied.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with choosing the modulus of elasticity and the thickness of the material in said panel and the modulus of elasticity and the thickness of the material in said permanently magnetised strips in relation to each other so that axial stress appearing will be small or non-existent for the forces that will act within the area of the attachment means or the layer.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with, in a panel of previously known type suitable for a display system, being able to create such prerequisites that the permanently magnetised strips can be thin and in any case assigned a thickness of less than 1.0 mm.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with selecting the thickness of the permanently magnetised strip as 0.2-0.8 mm, preferably 0.6-0.75, e.g. about 0.7 mm.
It should also be deemed a technical problem to be able to create a magnetic strip from a resilient plastic material or plastic compound having a modulus of elasticity exceeding 60 MPa and normally less than 200 MPa, where the magnetic field strength is generated by a magnetised granular material of the metal neodymium or equivalent.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with selecting the magnetisation direction of the strip N-S in the thickness or transverse direction of the strip.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with choosing the same magnetisation direction along the whole length of the strip.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with said strip, independently of its use, consisting of a strongly magnetic section and a non-magnetic section, and with an adhesive means extending over these two sections.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with allowing the magnetic section to be strip-edge-related and arranged to offer sufficient magnetic attractive force, which can be achieved by the magnetised section covering less than ⅓ of the width of the strip.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with choosing the magnetic section to be greater than 10% of the width of the strip.
A technical problem is also entailed in being able to perceive the significance of and advantages associated with allowing a first strip magnetised in N-S direction to be assigned a colour deviating from the colour of the second strip magnetised in S-N direction.
Solution
The present invention is based on an arrangement enabling edge-to-edge joining, by means of a magnetic attractive force, of a first edge portion of a first panel in a display system to a second edge portion of a second panel, a first magnetised strip being applied to said first edge portion and a second magnetised strip being applied to said second edge portion, the magnetised strips being assigned such magnetisation directions that, in a position where the edge portions are in proximity and/or co-operating with each other, they assume a position attracted to each other, and said strips consisting of a material different from the material of the panel and with means attaching the strip to the panel attached close to said edge portions.
In such an arrangement, specifically to solve one or more of the technical problems listed above, the present invention advocates that the modulus of elasticity and the thickness of said panel and the modulus of elasticity and the thickness of said strips shall be such in relation to each other that only small axial stress related forces, or none at all, will act within said attachment means, and that said strips shall be assigned a thickness suitable for this purpose that shall in any case be less than 1.0 mm.
As proposed embodiments falling within the scope of the present invention it is recommended that the modulus of elasticity for said panel may be selected for a plastic material within the range of 2000 to 3500 MPa and/or that the modulus of elasticity for said magnetic strips may be selected within the range of 60-200 MPa.
The present invention also advocates that the thickness of the strip may be selected as 0.2-0.8 mm and contain magnetic granular material of the metal neodymium.
Particularly recommended is for the magnetisation of one strip to be selected N-S in the transverse direction and for the same magnetisation direction to be chosen along the whole length of the strip.
The invention further recommends, independently of the application mentioned above, that said magnetic strip shall consist of a first magnetic section and a second non-magnetic section, the magnetic section may in the application referred to above be strip-edge-related.
The strip arrangement having two sections may be designed to cover less than ⅓ of the width of the strip.
The invention recommends that, when neodymium magnets are used, the magnetic section shall be chosen greater than 10% of the width of the strip.
The invention recommends assigning different colours for the first magnetised strip and the second magnetised strip.
It is also recommended that the attachment means used shall consist of an adhesive layer covering said section.
Advantages
The advantages that may primarily be deemed to characterise an arrangement in accordance with the present invention are that prerequisites are thereby created to assign a panel in a display system a rolled-up state wherein the radius of curvature can be chosen considerably smaller than the radius of curvature applicable for conventional rollable panels and wherein a modulus of elasticity and a thickness of said panel and a modulus of elasticity and a thickness of the magnetised strip or strips are such in relation to each other that only small axial stress related forces, or none at all, will act within said attachment means used.
It is furthermore advocated that the magnetised strip should be assigned a thickness which, at least in normal cases, shall be less than 1.0 mm.
Furthermore a strip arrangement having two sections may be used and the cost for the production of such a magnetic strip is less than for a full magnetic strip arrangement yet the adhesive attachment force may be the same.
The features primarily considered characteristic of an arrangement in accordance with the present invention are specified in the characterising part of claim 1.